Query logging

Query logging can be enabled by setting query_log directive in searchd section of the configuration file

searchd {
...
    query_log = /var/log/query.log
...
}

Queries can also be sent to syslog by setting syslog instead of a file path.

In this case all search queries will be sent to syslog daemon with LOG_INFO priority, prefixed with [query] instead of timestamp. Only plain log format is supported for syslog.

Logging format

Two query log formats are supported. Plain text format is still the default one. However, while it might be more convenient for manual monitoring and review, but hard to replay for benchmarks, it only logs search queries but not the other types of requests, does not always contain the complete search query data, etc.

The default text format is also harder (and sometimes impossible) to replay for benchmarking purposes. The sphinxql format alleviates that. It aims to be complete and re-playable, even though at the cost of brevity and readability.

Plain log format

By default, searchd logs all successfully executed search queries into a query log file. Here’s an example:

[Fri Jun 29 21:17:58 2007] 0.004 sec 0.004 sec [all/0/rel 35254 (0,20)] [lj] test
[Fri Jun 29 21:20:34 2007] 0.024 sec 0.024 sec [all/0/rel 19886 (0,20) @channel_id] [lj] test

This log format is as follows:

[query-date] real-time wall-time [match-mode/filters-count/sort-mode total-matches (offset,limit) @groupby-attr] [index-name] query

• real-time is a time measured just from start to finish of the query
• wall-time like real-time but not including waiting for agents and merging result sets time

Match mode can take one of the following values:

• “all” for SPH_MATCH_ALL mode;
• “any” for SPH_MATCH_ANY mode;
• “phr” for SPH_MATCH_PHRASE mode;
• “bool” for SPH_MATCH_BOOLEAN mode;
• “ext” for SPH_MATCH_EXTENDED mode;
• “ext2” for SPH_MATCH_EXTENDED2 mode;
• “scan” if the full scan mode was used, either by being specified with SPH_MATCH_FULLSCAN

Sort mode can take one of the following values:

• “rel” for SPH_SORT_RELEVANCE mode;
• “attr-” for SPH_SORT_ATTR_DESC mode;
• “attr+” for SPH_SORT_ATTR_ASC mode;
• “tsegs” for SPH_SORT_TIME_SEGMENTS mode;
• “ext” for SPH_SORT_EXTENDED mode.

Note: the SPH* modes are specific to SphinxAPI legacy interface. SQL and HTTP interface will log in most cases ext2 for matching mode and ext and rel for sorting modes.

If Manticore was started with --iostats (ot it was enabled via SET GLOBAL iostats=1) the corresponding metrics will be included in the log. Then a query log entry might take the form of:

[Fri Jun 29 21:17:58 2021] 0.004 sec [all/0/rel 35254 (0,20)] [lj] [ios=6 kb=111.1 ms=0.5] test

where: * ios - the number of file I/O operations carried out * kb - amount of data in kilobytes read from the index files * ioms - time spent on I/O operations

If Manticore was started with --cpustats (ot it was enabled via SET GLOBAL cpustats=1) metric cpums will be included in the log. The query log will then look like this:

[Fri Jun 29 21:17:58 2021] 0.004 sec [all/0/rel 35254 (0,20)] [lj] [ios=6 kb=111.1 ms=0.5 cpums=0.3] test

where cpums is time in milliseconds spent on CPU processing the query.

SQL log format

SQL format can be enabled by searchd directive query_log_format:

searchd {
...
    query_log = /var/log/query.log
    query_log_format = sphinxql
...
}

In this format, the example from the previous section would look as follows. (Wrapped below for readability, but with just one query per line in the actual log.)

/* Fri Jun 29 21:17:58.609 2007 2011 conn 2 real 0.004 wall 0.004 found 35254 */
SELECT * FROM test WHERE MATCH('test') OPTION ranker=proximity;

/* Fri Jun 29 21:20:34 2007.555 conn 3 real 0.024 wall 0.024 found 19886 */
SELECT * FROM test WHERE MATCH('test') GROUP BY channel_id
OPTION ranker=proximity;

Note that all requests would be logged in this format, including those sent via SphinxAPI and SphinxSE, not just those sent via SQL. Also note, that this kind of logging works only with plain log files and will not work if you use ‘syslog’ service for logging.

The features of Manticore SQL log format compared to the default text one are as follows.

• All request types should be logged. (This is still work in progress.)
• Full statement data will be logged where possible.
• Errors and warnings are logged.
• The log should be automatically re-playable via SphinxQL.
• Additional performance counters (currently, per-agent distributed query times) are logged.

Use sphinxql:compact_in to shorten your IN() clauses in log if you have too many values in it.

Every request (including both SphinxAPI and SQL) request must result in exactly one log line. All request types, including INSERT, CALL SNIPPETS, etc will eventually get logged, though as of time of this writing, that is a work in progress). Every log line must be a valid Manticore SQL statement that reconstructs the full request, except if the logged request is too big and needs shortening for performance reasons. Additional messages, counters, etc can be logged in the comments section after the request.

Logging only slow queries

By default all queries are logged. If it’s desired to log only queries with execution times that exceed the specified limit, the query_log_min_msec directive can be used:

searchd {
...
    query_log = /var/log/query.log
    query_log_min_msec  = 1000
...
}

The expected unit of measure is milliseconds, but time suffix expressions can be used as well, like

searchd {
...
    query_log = /var/log/query.log
    query_log_min_msec  = 1s
...
}

Log file permission mode

By default the searchd and query log files are created with 600 permission, so only the user under which server runs and root users can read the log files. query_log_mode allows settings a different permission. This can be handy to allow other users to be able to read the log files (for example monitoring solutions running on non-root users).

searchd {
...
    query_log = /var/log/query.log
    query_log_mode  = 666
...
}